1. Field of the Invention
The present invention is directed to fat compositions, hard butters, hard butter confectioner's compositions, and highly flavored fat containing compound coatings having an improved gloss retention and an increased resistance to fat migration and fat bloom. More particularly, the invention relates to a fat bloom inhibitor for edible fat compositions such as chocolate and flavored hard butter compound coatings which can be added directly to the composition during processing.
2. Background of the Invention
The food and chocolate industry has consistently been contending with the phenomena known as fat bloom or chocolate bloom. Fat bloom is generally associated with the migration of fats toward the surface and the appearance of a white or light grey colored deposit on the surface of chocolate. Prior to the time the white deposit is visible, the product usually becomes dull and hazy having lost the high gloss surface. Although taste and texture of the overall product may not be seriously altered by the early stages of fat bloom the dull appearance and white deposit make it look old, stale and unappetizing to the consumer. Fat bloom, as a consequence, results in a loss of sales and increased handling and production costs to the manufacturer.
The problem of fat bloom of hard butter compound coatings and chocolate is extremely complex and believed to be caused by a number of independent factors often times with no correlation between them. The actual cause of fat bloom is not fully understood although several theories have been proposed. The principal of fat bloom is generally understood to be the migration of fats to the surface where they recrystallize. The fat crystals grow in size over time to produce a dull appearance on the surface. As the crystals grow still larger, the light colored deposit appears. It is this light colored deposit which is commonly referred to as fat bloom. Factors which are known to promote the occurrence of fat bloom include prolonged storage at high temperatures followed by cool temperatures, and cyclic temperature changes over a period of time such as may occur during shipping and handling.
Chocolate, chocolate coatings and chocolate flavored hard butter coatings are particularly prone to fat bloom. Chocolate is an intimate mixture of cocoa butter, sugar, cocoa particles and lecithin. Optional ingredients such as milk solids, vanilla flavoring and nuts may be added. The cocoa butter in chocolate is known to be present in at least three polymorphic forms. The polymorphic behavior of cocoa butter is believed to be a contributing cause of fat bloom in chocolates. The presence and ratio of the different polymorphic forms is, at least in part, dependent on the processing conditions and tempering of the chocolate. The different crystal forms of the cocoa butter are most readily identifiable by their melting points and x-ray diffraction pattern corresponding to the different molecular orientations.
Solid fats as a class tend to exhibit polymorphism. Polymorphism is generally described as the ability of the solid to exist in several different crystalline forms. The different crystal forms have a marked effect on the melting point of the fat.
The crystalline forms of cocoa butter have different energy potentials such that those with the higher energy potential (free energy) are less stable and tend to transform to the configuration of the low energy form. The stability is generally attributed to the chair configuration about the triglyceride linkage and the ability of the molecules to stack on each other in a lattice-like fashion resulting in tighter packing. The stable form has the highest melting point of the different crystal forms and is the preferred form in manufacturing most products.
When the comparatively unstable crystalline forms transform to the stable form, considerable amounts of energy are released as heat causing a temporary increase in the amount of liquid phase in the chocolate. It is believed the liquid phase tends to dissolve the higher melting crystal fractions, which then migrate to the surface where they recrystallize to form fat bloom. It is therefore desirable to have the fat present in the stable crystal form or at least increase the ratio of the stable form in the fat mixture. The desirability of the more stable form is also due to its resistance to migrate compared to the other crystal forms. One proposed theory for the resistance to migration is the tighter packing of the lattice structure formed by the chair configuration of the crystals. The lattice is formed by adjacent crystals stacking on each other in an inverted position. The lattice has been proposed to form a network of crystal lamella functioning as a barrier to inhibit the migration and recrystallization of the fat.
The presence of the crystalline forms and their instability ar evident by a comparison of the Differential Scanning Calorimetry (DSC) melt profiles over a period of time. DSC essentially records and charts the melting points or melting range of the various components of a composition. The height of individual peaks are generally in proportion to the approximate ratios of the amount of components present. The cocoa butter in chocolate, for example, can reveal three or more peaks corresponding to the different crystal structures. A series of DSC profiles carried out over a period of weeks and months show a gradual merging of the peaks toward a single peak corresponding to the most stable form. This reduction in the height of some of the peaks demonstrates the conversion of the relatively unstable crystal form into the more stable form.
A cocoa butter composition, such as chocolate, having a substantial portion of the fat in the stable form has shown a lesser tendency to fat bloom and a longer gloss retention of the surface over an extended period of time compared to some confectioner's compositions or hard butters. The industry has sought to increase the concentration of the stable forms and to stabilize the fats in the composition by the use of various chemical additives and chemical modifications to immobilize the fat crystals.
In the manufacture of chocolate and confectioner's compositions, careful control of the processing steps are known to effect the loss of gloss and the rat and extent of fat bloom. This is particularly true in the chocolate enrobing of fat based centers. For example, as described in "Studies On The Formation Of Fat Bloom And Methods Of Delaying It" Rev. Intern. Choc. 16, pg 345-68 (1961) controlling the temperature of a fat based center is essential to achieve a stable chocolate coating having a high gloss retention and good texture. The fat from the center may tend to migrate into the coating thereby changing the composition of the coating. The coating of cold centers with the melted chocolate tend to develop a multitude of fine hairline cracks and prevent proper crystal growth. These cracks are generally due to the sudden setting of the coating over the cold center but have also been attributed to a rapid external cooling followed by syneresis. These hairline cracks are believed to promote fat bloom in the coating and in particular those with a high fat center. The general practice is to pre-warm the centers thoroughly before coating and to gently cool the coated product over a period of time to reduce the formation of the cracks.
In addition to proper cooling of the chocolate, fat bloom is dependent on the proper tempering of the chocolate. Tempering is generally the controlled heating to melt fat crystals and cooling under controlled conditions to a predetermined temperature to obtain small fat crystals in as stable form as possible. Chocolate should have a high gloss and a hard clean break. The high gloss and texture is achieved only by the presence of minute stable fat crystals evenly dispersed throughout the fat system. Fat bloom can be appreciably retarded when there is a complete dispersion of the non-fat components in the fat to form a continuous uninterrupted layer of fat.
Hard butter and confectioner's coatings containing hard butter differ from the relatively predictable nature of cocoa butter since hard butters are usually made up of a very large number of different triglycerides and fatty acids. Hard butters may be made from several vegetable fats and contain as many as 10-80 different components. These different components tend to behave as if made up of a single component. When solidified and crystallized, the compound exhibits a single, although sometimes broad, melting point range. Some of these compositions, on the other hand, tend to exhibit self-fractionation. Self-fractionation occurs when some of the components form distinct crystals separate from the composition and act as different components which have a different melting point range from the rest of the composition. This complex nature of the fractionation of hard butter compositions is more likely the cause of the fat bloom, rather than polymorphism as is speculated for cocoa butter. In direct contrast, the characteristics of hard butter and confectioner's compositions, chocolate and cocoa butter are almost entirely due to the polymorphic behavior of the triglycerides. In view of these differences between hard butter and cocoa butter, a component which has been effective in retarding fat bloom in cocoa butter may not necessarily be effective in controlling bloom in hard butter compositions.
Compound coatings which are unfractionated are generally prone to self-fractionation and fat bloom. The compositions which have been fractionated may demonstrate a decreased tendency to self-fractionate and produce fat bloom, although fractionation is not cost effective in commercial operations.
Numerous attempts have been made in the past to inhibit fat bloom by chemical modification of the cocoa butter glycerides by selective hardening and transesterification or by the inclusion of various chemical additives. These efforts have demonstrated only limited success in inhibiting fat bloom while exhibiting a number of adverse side effects and increased production costs.
Some of the chemical additives which have been somewhat effective in inhibiting fat bloom in chocolate are not commercially feasible due to the alteration of the flavor and texture. A satisfactory bloom inhibitor must prolong the shelf life of the product by retaining the gloss without changing the taste, sweetness or texture. Similarly, the inhibitor should have no aftertaste and should not alter the melting point of the chocolate.
One such effort is disclosed in U.S. Pat. No. 4,664,927 relating to the immobilizing of the normally flowable fats at temperatures above their normal melting point. The procedure provides for the addition of a liquid polyol, such as glycerine, to increase the viscosity of the system by reacting with the fat in the liquid phase. The increase in viscosity is intended to prevent the chocolate product from melting at low temperatures and from adhering to the wrapper. The process does not address the problem of fat bloom. In addition, the gloss retention is not enhanced by the addition of the liquid polyols containing at least one pair of vicinal hydroxyl groups.
One type of fat bloom inhibitor is described in U.K. Patent Application 2,108,071A which employs a triglyceride composition having a 30-100% by weight C.sub.50 -C.sub.52 fatty acid content and an iodine value of 0.5. The preferred glycerides include the fully hydrogenated oils of palm, cottonseed, rice, corn, illipe butter, cocoa butter, phulwara butter and fractionated milk fat. These compounds are stated to be effective in inhibiting fat bloom without resulting in a waxy or firm texture that has been characteristic in the use of highly saturated fats.
Japanese Patent Nos. 7304543-R and 7304544-R describe a similar type of additive to enhance anti-blooming properties of chocolate. The described inhibitor comprises a hardened butter from hydrogenated castor oil and a hardened lard fraction. The resulting hardened butter is then added to a prepared chocolate and processed under conventional procedures.
Still another use of triglycerides to attempt to inhibit fat bloom is described in Momura U.S. Pat. No. 4,726,959. In this composition the bloom inhibitor comprises a mixture of triglycerides of both saturated and unsaturated fatty acids. Canadian Patent No. 823,141 discloses a method of controlling fat bloom by the addition of interesterified triglycerides.
As reported in Kleinert, "Formation Of Fat Bloom and Methods Of Delaying It" Rev. Intern. Chocolate. Vol. 16, 345-68 (1961) a few of the glycerides which have shown some fat bloom inhibiting effects include Biscuitine fat, hardened arachis fat and butter fat. The results from this study report that to achieve the fat bloom inhibiting effects, the processing conditions, such as cooling and tempering, must be carefully controlled.
The previously employed methods of inhibiting fat bloom in chocolate have experienced only limited success due to the undesirable changes in the texture, mouth feel, melting point and taste of the final product.
Extensive research has been conducted to develop effective bloom inhibiting additives which can be combined directly with the triglyceride composition. A few of these additives which have shown some bloom inhibiting characteristics have been reported in Cerbulus, "The Effects of Various Substances On The Blooming Of Chocolate", Journal of Food Technology Vol. 4, 133-140 (1969). For example, chocolate containing additional quantities of the triglyceride tripalmitin is reported to have no tendency to bloom and no adverse flavor changes. On the other hand, the additives Deft 37 (trademark) and Edelfette (TDM) (trademark) improved the bloom resistance of samples tested, but were unacceptable due to the waxy taste.
Examples of other additives which have been ineffective in controlling or retarding bloom in cocoa butter include hydrogenated butter fat, butylated hydroxy anisole (BHA), glycerol and various amino acids. Moreover, the hydrogenated butter fat produced an unpleasant taste while BHA resulted in an unsightly white appearance with a granular texture.
Anhydrous glucose has been shown to produce a high resistance against fat bloom in proportions amounting to 15%-20% by weight of the chocolate. Glucose, however, resulted in a distinct aftertaste in the throat after eating.
Other compounds that have been suggested for possible fat bloom prevention with only limited success include amino acids such as alpha amino N-butyric acid, glycine, cysteine and glutamic acids, bile acids, cetyl alcohol, cholesterol, choline-HCL, citric acid monoglyceride, lactose, low HLB sucrose polyesters, maltrins, methionine, polymerized cocoa butter, phytic acid, polyglycerol fatty esters, polyoxyethylene sorbitan monostearate, propylene glycol fatty acid esters, sorbitan monolaurate and monostearate, and taurine. Although many different types of compounds have been suggested for use as fat bloom inhibitors, they have generally proved to be unacceptable in commercial practices.
There is accordingly a need for an effective additive which will enable a hard butter, confectioner's composition and chocolate to retain its gloss, prolong shelf life and inhibit the formation of the white crystalline fat deposits on the surface without having an adverse impact on the flavor of the finished food product.
The present invention is therefore directed to an effective bloom inhibiting additive which prolongs the gloss of hard butter, chocolate, and other hard butter based systems such as confectioner's coatings and prevents the formation of fat bloom on the surface of the product. The additives according to the invention do not adversely affect the sweetness, taste or texture of the finished product.